1. Field of the Invention
The present invention relates to a natto food, and more particularly to the natto food which is made more easily eatable by blending soybean flour and/or edible fiber to natto powder thereby masking a peculiar smell for easier eating.
2. Background Art
Conventionally, many methods of manufacturing powdered natto which is a fermented soybean product are proposed, such as a method of producing active dry natto by adding cellulase, protease and the like for fermentation in a process for inoculating Bacillus Natto to soybean as law material, fermenting the mixture, and drying it by the combination of wind velocity drying and freeze vacuum drying method (Japanese Patent Publication No Sho 49-21783), a method of producing powdered natto by cooling the natto below 5.degree. C. in advance, crushing and powdering after vacuum freezing and drying (Japanese Patent Application Laid-Open No. Sho 50-70545) and others (Japanese Patent Publication Nos. Sho 57-9344 and 63-48509). Thus, these methods for drying and powdering the natto by utilizing the vacuum freeze and dry method are publicly known.
Also, a method of processing natto by separating the natto into an outer layer portion and an inner layer portion after vacuum freezing and drying the natto and then powdering it (Japanese Patent Publication No. Sho 54-34820) and a method of producing a health food by separating natto into the outer layer portion and the inner layer portion after vacuum freezing and drying the natto crushing the outer layer portion and adding and mixing lecithin to the crushed outer layer portion (Japanese Patent Application Laid-Open No. Sho 55-19037) are also proposed. In addition, a method of preparing granulated natto after adding an emulsifier into the natto powder has been already tried.
However, these try to obtain powdered dry natto which can be well preserved while maintaining the properties of raw natto, or these are the processing methods for effective utilization of each part of the natto or the methods for processing efficiently.
These conventional powdered dry natto has the following shortcomings:
(a) If the natto is used as dry powder, it is easily scattered and handling becomes more difficult. Moreover, the powdered natto has a poor dispersibility during use. Even though it is utilized by dissolving in water or hot water, granular solids are created and this is troublesome for work. When the granular solids created are eaten, they stick to the oral cavity and are sticky to the touch and this gives very rough feeling when eating. PA1 (b) Normally, when the natto powder is processed as it is to the granules, stickiness occurs if moisture is added, thereby making the granulation difficult and moreover the granules obtained will strongly retain the peculiar smell of the natto. PA1 (c) When various emulsifiers are added to the natto powder for granulation purpose, the problems stated above are slightly improved but the peculiar smell of natto still remains considerably, so that the range of its use is likely to be limited.